Commonwealth legislative power is vested in the Commonwealth Parliament, comprising the House of Representatives and the Senate. There are currently 226 members of the Parliament (MPs) - 150 members of the House of Representatives and 76 Senators.

Powers of Parliament

Apart from the constitutional requirement that all financial legislation must originate in the House of Representatives and that the Senate cannot amend such legislation, the two houses have similar powers. The fact that the Senate can reject financial legislation makes it potentially one of the most powerful upper houses in the world.

As Australia has a federal system of government, the formal powers of the Commonwealth Parliament are constitutionally limited to areas of national importance such as trade and commerce, taxation, postal services, foreign relations, defence, immigration, naturalisation, quarantine, currency and coinage, weights and measures, copyright, patents and trade marks. However, High Court decisions, Commonwealth-state agreements and use by the Commonwealth of the constitutional power to make grants to the states and territories, have seen the Commonwealth gain influence in regard to various other matters including industrial relations, financial regulation, companies and securities, health and welfare, and education.

The formation of a government is the most important outcome of a general election. Either the government is returned by virtue of retaining a majority of seats in the House of Representatives, or the opposition party or a coalition of parties wins a majority of seats, resulting in the formation of a new government. A new government could also be formed on any occasion between elections if the majority party changes its leader, or loses its majority (e.g. as a result of a by-election), or is defeated in an important vote in the House of Representatives. The last occurrence of government changing hands between elections occurred in October 1941.

More than half of Parliament's time is taken up with the consideration of proposed legislation. Between 150 and 250 Bills are passed each year. Most Bills are not contentious, either being 'machinery' legislation necessary for the orderly processes of government, or Bills that propose alterations to existing legislation. Most of the Bills are government Bills; legislation sponsored by private members is rare.

The representation of the people is an important role of members of the House of Representatives and Senators. Working for their constituents occupies a great deal of their time. The relative importance of this role may be judged by the high proportion of time spent by MPs in their electorates and away from Parliament. Since the beginning of 2000, Parliament has averaged 65 sitting days per year.

The scrutiny function is seen most obviously in the formal periods of Question Time, in both houses, that are part of each day's sitting. Question Time is the best-known part of parliamentary proceedings, and is attended by many of the visiting public. Less well-known is the activity of parliamentary committees which are established in order that Parliament's legislative, representation and scrutiny functions can be carried out thoroughly and with the benefit of expert advice. These committees undertake the scrutiny of government operations as well as frequent inquiries into a range of current issues.

Parliament also acts as a forum where peoples’ concerns can be aired prominently. This can be in Question Time, in debates on major issues, in grievance debates, in adjournment debates and at various stages of the legislative process.